Note the 4G plans will be limited to those which cost $29.95 or more per month. I believe you will be able to use any Verizon 4G phone then. A lot of details aren't clear yet but if you wish to follow this I suggest you follow Kitty Wireless forums (she is a major Page Plus dealer):
http://www.kittyforums.net/forumdisplay.php/164-4g-LTE-General-Page-Plus-Discussions
I expect other Verizon MVNOs will sooner or later also be able to offer 4G.
http://www.kittyforums.net/forumdisplay.php/164-4g-LTE-General-Page-Plus-Discussions
I expect other Verizon MVNOs will sooner or later also be able to offer 4G.